Astrobiological Complexity with Probabilistic Cellular Automata

Abstract

The search for extraterrestrial life and intelligence constitutes one of the major endeavors in science, but has yet been quantitatively modeled only rarely and in a cursory and superficial fashion. We argue that probabilistic cellular automata (PCA) represent the best quantitative framework for modeling the astrobiological history of the Milky Way and its Galactic Habitable Zone. The relevant astrobiological parameters are to be modeled as the elements of the input probability matrix for the PCA kernel. With the underlying simplicity of the cellular automata constructs, this approach enables a quick analysis of large and ambiguous space of the input parameters. We perform a simple clustering analysis of typical astrobiological histories with "Copernican" choice of input parameters and discuss the relevant boundary conditions of practical importance for planning and guiding empirical astrobiological and SETI projects. In addition to showing how the present framework is adaptable to more complex situations and updated observational databases from current and near-future space missions, we demonstrate how numerical results could offer a cautious rationale for continuation of practical SETI searches.

Population growth, energy use, and the implications for the search for extraterrestrial intelligence

“…This clustering of occupied worlds is predicted elsewhere. Several models of interstellar dispersion mediated by varying cultural tendencies (Vukotić & Ćirković 2012, Carrigan 2012 find that civilizations can get hemmed in by frontier worlds that become unlikely to continue the colonization process; this could be interpreted here as attaining sustainability. Provided that we find such a civilization in a dense massive star cluster or in under a Galactic rotation timescale (to mitigate the effects of differential rotation and shear), It may then be possible that the search for one communicating or thermally augmented world reveals many more next door to it.…”

‘Grandeur in this view of life’:N-body simulation models of the Galactic habitable zone

“…This is in accordance with our perceived absence of contact with extraterrestrials (with the usual assumptions of realism, scientific naturalism, and gradualism, cf.Ćirković, 2009). Absence of the contact was also explained, due to influence of habitability agents, by arguments of astrobiological phase transition resulting from an expected decrease in SFR (see Vukotić &Ćirković, 2012). In our model SFR sharply decreases after 3 Gyr which makes the results of this paper even more appealing in explaining the lack of perceiving aliens so far.…”

The basic rules for coexistence: The possible applicability of metalaw for human-AGI relations

“…To be more precise, a form of intelligence which arose without human intervention. The possibility that the ETI will take the form of "postbiological" beings [34] or that the contact will be established and carried out using AI probes or even Von Neumann probes [35] has been discussed in academic circles of SETI. However, in the case of metalaw the "form" or "embodiment" of ETI was less relevant than the issue of its existence.…”